Note: Descriptions are shown in the official language in which they were submitted.
H8324110CA
SELECTIVE CIRCULATION AND TRANSFER IN A
MOLTEN METAL FURNACE
Technical Field:
[1] This disclosure pertains to furnaces and pumps for molten metal and, in
particular, to
devices that enable circulation and transfer of the molten metal of the
furnace.
Background:
[2] A furnace such as a reverberatory furnace is used in molten metal
processing. The
furnace includes a main hearth where ingots and/or sows of solid articles of
metal to be melted
are placed on a sill from which they move into the hearth when melted. The
hearth is heated by
gas burners, for example. Some furnaces circulate the molten metal in the
furnace, for example,
using pumps of the types supplied by High Temperature Systems, Inc.
Circulation of the molten
metal is advantageous in that the molten metal is maintained at a more uniform
composition and
temperature; also, less heat may be required to maintain the molten metal
temperature.
[3] Various devices are used to transfer molten metal out of the furnace.
Some furnaces
include an opening for tapping the metal of the furnace. This can be hazardous
and difficult as
the opening may not remain clean over time and may not be sealed effectively.
[4] An effective device is the unique patented ChameleonTM pump supplied by
High
Temperature Systems, Inc. as disclosed in U.S. Patents 7,507,365 and
7,687,017. This is a
multifunctional pump that moves an impeller inside an impeller chamber
directing the molten
metal to different outlets, permitting circulation, transfer or both, using a
single pump. A
stationary riser extends from the pump to a vessel located outside the
furnace, such as above a
ladle or crucible. When the pump moves the impeller to transfer mode, the
molten metal leaves
the pump, travels along the riser and enters the vessel. Circulation could
occur simultaneously
with the transfer, or at different times.
1
CA 2931538 2017-08-01
CA 02931538 2016-05-30
H8324110CA
[0005] Molten Metal Equipment Innovations Inc. disclosed pump systems to
achieve molten
metal transfer from the furnace (see U.S. Patents Nos. 9,205,490; 8,337,746;
and 9,156,087) but
they require substantial furnace down time to install. The furnace must be
emptied and cooled.
Then a separate chamber is constructed adjacent the furnace. A dedicated
transfer pump is
disposed in the chamber to enable transfer of molten metal from the furnace.
This system is
disadvantageous in view of the substantial loss in metal processing due to the
furnace down time
and the cost of constructing another chamber made of refractory. Most
importantly, this system
is limited in that the pump that is used cannot also carry out circulation but
is limited to only
molten metal transfer.
Summary of the Disclosure:
[0006] One aspect of the present disclosure features a furnace that is
capable of selective
circulation and transfer of molten metal. The furnace includes a main hearth
and a pump well for
containing molten metal. A pump disposed in the pump well pumps the molten
metal. A first
refractory wall is disposed between the pump well and the main hearth. The
first refractory wall
includes a first opening permitting passage of molten metal from the main
hearth through the
wall into the pump well. A second refractory (pump) wall is disposed in the
pump well
downstream of the pump. The pump wall includes a second opening permitting
movement of
molten metal out of the pump well through the pump wall opening, into an
optional scrap
charging well and back into the main hearth. A device for selective
circulation and transfer of
molten metal includes a movable transfer passageway disposed downstream of the
pump wall
that is adapted to be aligned with the pump wall opening and to extend toward
an exterior vessel
disposed outside of the furnace. When the movable passageway is positioned in
alignment with
the pump wall opening the molten metal is transferred from the furnace to the
vessel outside the
furnace, for example, to a ladle or crucible. When the passageway is moved out
of alignment
with the pump wall opening, the pump moves the molten metal through the pump
wall opening
and circulates it in the furnace.
[0007] Specific features of the first aspect of the disclosure will now be
described which may
be used in any combination. The transfer passageway can be formed in a
transfer block of
(eastable) refractory material. This transfer block can be heavy so as to
resist a force of pumped
2
CA 02931538 2016-05-30
H8324110CA
molten metal through the second opening in the pump wall and to remain in
contact with the wall
during pumping.
[0008] Yet another specific feature is a device for achieving selective
circulation and transfer
of molten metal which includes the following components. A support structure
is fixedly
disposed over the furnace. Pulleys are carried by the support structure. An
actuator (e.g.,
pneumatic or hydraulic cylinder) is disposed outside the furnace. For example,
the actuator can
be placed on the floor outside the furnace so as to be away from the heat of
the furnace. A cable
is fastened at one end portion to the transfer block and at another end
portion to the actuator and
extends around the pulleys. One stroke of the actuator moves the cable so as
to move the block
upward out of alignment with the second opening and to carry out circulation
of molten metal in
the furnace. This is because the pump wall opening is unobstructed. Another
(e.g., opposite, up)
stroke of the actuator permits the transfer block to move downward into
alignment with the
pump wall opening to carry out transfer of the molten metal to the exterior
vessel. This
movement may occur mainly as a result of the weight of the transfer block
moving it downward
when the cable tension is released or the movement may be more rigidly
regulated depending on
the structure connecting the transfer block to the cylinder or other actuator.
[0009] It should be appreciated throughout the disclosure that this is
merely one example of a
suitable device for moving the transfer passageway and that variations can
occur without
departing from the aspects of the present disclosure. For example, up and down
strokes may
achieve the opposite movement of the transfer block than described in this
disclosure and shown
in the drawings, items other than metal cable (e.g., chain), or different
types of cables may be
used. Actuators besides cylinders may be employed (e.g., a screw drive for
moving the cable).
[0010] In yet another specific feature a metal transfer conduit is fastened
to the transfer block
and extends from the transfer passageway outside the furnace to a location
above the vessel. A
plate or flanged conduit may be cast into the transfer block. For example, the
plate may include
threaded openings and optional bolts. A flange of the conduit may be connected
to the cast plate,
for example, including threaded openings in the flange aligned with the bolts
of the plate and
fastening nuts to them. On the other hand, a flanged conduit can be cast into
the refractory so as
3
CA 02931538 2016-05-30
H8324110CA
to enable another flanged conduit to be fastened to it. When the transfer
block is lowered to its
transfer position the conduit moves from a location above the vessel to closer
to an upper mouth
of the vessel, reducing splashing of molten metal and avoiding detrimental
generation of oxides.
[0011] Another specific feature is that the transfer block is formed of a
castable refractory.
One composition of the transfer block is a mixture of aluminum oxide and
silicon carbide. The
particular refractory composition used in a High Temperature Systems Inc.
Coriolis block may
be employed for the transfer block.
[0012] Yet another specific feature is that an optional scrap charging well
is disposed
downstream of the pump well. The first refractory wall is also disposed
between the scrap
charging well and the main hearth. This wall includes a third opening enabling
molten metal to
move from the scrap charging well into the main hearth.
[0013] A second aspect of the disclosure is a kit for retrofitting existing
furnace for selective
circulation and transfer with minimal effect on molten metal processing
operations during its
construction. This kit would permit a simple and cost effective way for the
furnace to have
selective molten metal circulation and transfer using only a single pump. The
kit includes a
transfer passageway adapted to be disposed downstream of the refractory pump
wall and to
extend from alignment with the opening in the pump wall toward the exterior
vessel outside of
the furnace. Included are means for moving the transfer passageway into
alignment with the
opening and against the pump wall so as to enable pumped molten metal to be
transferred from
the furnace along the passageway to the exterior vessel, and for moving the
transfer passageway
out of alignment with the opening so as to enable pumped molten metal to
circulate in the
furnace.
[0014] Specific features of the above kit that may be used in any
combination will now be
described. Included as a specific feature is that the transfer block of
refractory material is
adapted to be disposed downstream of the pump wall. The transfer block
includes the transfer
passageway that extends from alignment with the opening in the pump wall
toward the exterior
vessel. The transfer block optionally includes a face that slides on the pump
wall. Further
4
CA 02931538 2016-05-30
H8324110CA
included is the support structure adapted to be fixed over the furnace.
Pulleys are carried by the
support structure. An actuator (e.g., pneumatic or hydraulic cylinder) is
positioned outside the
furnace. A cable is fastened at one end portion to the transfer block and at
another end portion to
the actuator and extends around the pulleys. When actuated in one (e.g., down)
stroke the
actuator moves the cable so as to move the transfer block upward out of
alignment with the
pump wall opening to cause molten metal circulation. When actuated in another
(e.g., up) stroke
the actuator permits the transfer block to move downward (optionally sliding
against the pump
wall) into alignment with the pump wall opening to carry out transfer of
molten metal from the
furnace to the vessel.
[0015] In another specific feature the kit can include the transfer conduit
fastened to the
transfer block and extending from the transfer passageway outside the furnace
to a location
above the vessel. This transfer conduit can be formed of metal, e.g., steel.
[0016] In a third aspect, the furnace can be modified so as to employ the
kit of the disclosure
by building the support structure above the furnace, e.g., fixed to the top of
the pump wall of the
furnace. The support structure would include the pulleys rotatably fastened to
it. The support
structure and pulleys would be formed of heat resistant materials, e.g.,
steel. The transfer block
would be cast so as to include the transfer passageway inside of it. This
would be dimensioned
so as to fit the particular furnace design. For example, the passageway would
be cast into the
block at a location where it would be capable of being aligned with the
archway in the pump wall
when the transfer block rests on the floor of the furnace and to extend to a
sufficient elevation so
as to enable the conduit to be connected to the transfer block. The conduit
could also be tailored
so as to extend at a suitable angle and length to accommodate the location and
size of the exterior
vessel (e.g., ladle or crucible) to which the molten metal is transferred. The
cylinder would be
positioned exterior of the furnace to keep it away from the intense heat of
the furnace. The cable
would be fastened to the cylinder and the transfer block and would travel over
the pulleys.
[0017] Those skilled in the art would realize in view of this disclosure
that the transfer and
circulation operations could be remotely controlled and even automated using a
touch screen for
user input, and a programmable logic controller that would enable signals to
be sent to actuate
H8324110CA
the cylinder or other actuator and to control the timing of its up and down
strokes. Further,
safety measures could be employed such as the use of IR sensors which would
sense volume or
height of molten metal transferred to the vessel and when a maximum is
reached, to
automatically cause the cylinder to be actuated in its down stroke to end
molten metal transfer to
the vessel, or to cease operation of the pump, and the like.
[18] The device of the present disclosure is advantageous in that it
permits circulation and
transfer of molten metal of a furnace using a single pump. This is a
versatility so far only
achieved by the Chameleon pump by High Temperature Systems Inc. In addition,
little or no
furnace down time is needed for its construction. No separate costly
refractory chamber needs to
be built. Despite these cost advantages, this device even outperforms other
existing devices. Not
only can it simply and inexpensively achieve molten metal transfer, but the
same pump is able to
carry out circulation, which is not achieved by simple conventional molten
metal pumps. For
example, the Molten Metal Equipment Innovations pump is dedicated to transfer
and cannot
achieve the dual circulation and transfer functions of the present device. In
addition, the present
device can be employed in various types of furnaces and cleanliness of molten
metal even in so
called dirty metal environments, for example, where automotive components are
melted and
leave unmeltable articles in the bath. Finally, the present device is
versatile in that it does not
require a specific pump to be used.
[19] Examples of suitable pumps are disclosed in U.S. Patents Nos.
9,057,377 and
9,074,601 to Thut, when designed as a discharge pump and other discharge pumps
made by High
Temperature Systems Inc. Suitable pumps for pumping molten metal of the type
that include a
motor driven impeller, such as those made by High Temperature Systems Inc.,
position the
impeller on the end of a shaft inside an impeller chamber of an elongated base
having an inlet
and outlet from the impeller chamber. The base is submerged in the molten
metal. The impeller
chamber may include a volute. Upon rotation of the impeller, molten metal is
drawn into the
base into the impeller chamber and then travels to the outlet of the base. If
the pump is a
circulation or submerged discharge pump, as is suitable in the aspects of the
present disclosure,
the outlet of the base extends as a passageway to the outer surface of the
base, which circulates
the molten metal through the furnace. All of the
6
CA 2931538 2017-08-01
CA 02931538 2016-05-30
H8324110CA
components of the pump that are in the molten metal environment are typically
made of
refractory material such as graphite, ceramic, graphite with a ceramic
covering or graphite
impregnated with a refractory oxide.
100201 A transfer pump has features similar to those of the discharge pump
above, but the
outlet can lead to a fixed riser spaced apart from the shaft, which extends
above the pump to a
conduit which directs the molten metal to another location such as to a ladle
or to a die casting
machine.
[0021] The specific features of the first and second aspects can be used in
any combination.
These features can also be combined with any of the features described in the
Detailed
Description below.
[0022] It should be understood that the above Summary of the Disclosure
describes
embodiments of the disclosure in broad terms while the following Detailed
Description describes
embodiments of the disclosure more narrowly and presents specific embodiments
that should not
be construed as necessary limitations of the invention as broadly defined in
the claims. Many
additional features, advantages and a fuller understanding of the invention
will be had from the
accompanying drawings and the Detailed Description that follows.
Brief Description of the Drawings:
[0023] Figure 1 is a top view of a furnace including a device capable of
selective circulation
and transfer of molten metal according to the present disclosure;
[0024] Figure 2 is a cross-sectional side view of the furnace and device of
Figure 1;
[0025] Figure 3 is a front view of the furnace and device of Figure 1.
Detailed Description:
[0026] A furnace 10 is capable of selective circulation and transfer of
molten metal 12. The
furnace 10 includes a main hearth generally designated 14, a pump well 16 and
a scrap charging
7
CA 02931538 2016-05-30
H8324110CA
well 18 in a direction of molten metal circulation. The main hearth 14
contains molten metal and
includes a device for heating the molten metal, for example, gas fired
burners. The main hearth
may include a sill for receiving sows and/or ingots of solid metal for melting
into the main
hearth. A discharge pump 20 pumps the molten metal 12. A suitable pump may be
obtained
from High Temperature Systems, Inc. The pump well 16 contains molten metal,
the pump 20
being disposed in the pump well. A first refractory wall 22 is disposed
between the pump well
and the main hearth. The first refractory wall 22 includes a first opening or
archway 24
permitting passage of molten metal from the main hearth 14, through the wall
22 and into the
pump well. One side of the wall 22 is in the pump well and in the charge well
18 while the other
side of it is in the main hearth 14 as known in the art. The first refractory
wall 22 can extend for
much of the length of the main hearth. A second refractory (pump) wall 26 is
disposed so as to
include a face located in the pump well downstream of the pump 20. The pump
wall 26 includes
a second opening or archway 28 permitting passage of molten metal from the
pump well,
through the pump wall toward the scrap charging well 18. For example, a High
Temperature
Systems Inc. discharge pump may be positioned such that an elongated discharge
passageway of
the pump extends into the opening 28. Molten metal then is inlet into a base
of the pump into an
impeller chamber and discharged out of the discharge passageway leading from
the impeller
chamber, as a result of rotation of a motor driven rotor or impeller in the
impeller chamber.
Scrap is melted in the scrap charging well 18 in a known manner. The second
refractory wall 26
has a face disposed in the charge well. A third outer refractory wall forms
one side 30a of the
pump well, and a second side 30b of the pump well parallel to the hearth wall
22 and continues
parallel to the hearth wall 22 as an outer portion 30c of the scrap charging
well. This wall 30
may have a portion parallel to portion 30a at the opposite end of the furnace
that joins with the
main hearth wall 22.
[0027] The device of the present disclosure is suitable for use in any
molten metal, for
example, aluminum and zinc, but not limited to these examples.
[0028] Referring to Fig. 2, a device 32 for selective circulation and
transfer of molten metal
includes a movable transfer passageway 34 disposed downstream of the pump wall
26 relative to
a direction the circulating molten metal flows. The transfer passageway 34 is
adapted to be
8
CA 02931538 2016-05-30
H8324110CA
aligned with the pump wall opening 28 (e.g., Fig. 1) and extends toward an
exterior vessel 36
outside of the furnace for containing transferred molten metal. When the
movable passageway
34 is positioned in alignment with the pump wall opening 28 the pumped molten
metal is
transferred from the furnace to the vessel 36. Here the passageway completely
covers the pump
wall opening so that molten metal cannot pass the passageway 34 into the scrap
charging well
but must flow through the transfer passageway 34. When the transfer passageway
34 is moved
out of alignment with the pump wall opening 28, the pump 20 circulates the
molten metal in the
furnace.
100291 In one example, the transfer passageway 34 is formed in a transfer
block 38 of
refractory material having an inside face 40 that optionally slides on a
downstream face 42 of the
pump wall 26 that is located in the scrap charging well. An entrance 41 of the
transfer
passageway can be flared outward (Fig. 2). The transfer block 38 can be quite
heavy (e.g., over a
thousand pounds) so as to resist buoyancy in the molten metal and the force of
pumped molten
metal through the pump wall opening, and to remain near or in contact with the
pump wall face
42 and so as to cover the pump wall opening 28 during the transfer operation.
A conduit 39
formed of steel or the like can extend from a fixed connection with the
transfer block 38 in
alignment with the transfer passageway 34, to a location outside the furnace
above the vessel 36
(Fig. 3).
[0030] A support structure 44 is fixedly disposed over the furnace and can
include vertical
beams and a horizontal cross beam, made of steel. A steel plate can be
fastened to the top of the
furnace wall. The support structure 44 may be fastened onto a top of the pump
wall 26 and onto
the top of the outer wall 30b (and onto the steel plate). Pulleys 46 are
rotatably carried by the
support structure 44. A pneumatic or hydraulic cylinder 48 is disposed outside
the furnace. A
steel cable 50 extends between the cylinder 48 and the transfer block 38 and
across the pulleys
46. The transfer block can include a half ring 52 fixedly attached to it (Fig.
3) and the conduit 39
can include a half ring 54 fixedly attached to it. A full ring 56 can be used.
The cable 50 is
attached to and extends between the full ring 56 and the half ring 52 on the
transfer block. The
cable also attaches to the full ring 56 and the half ring 54 on the conduit.
The cable 50 also
attaches to the full ring 56 on one end portion and to the cylinder 48 at the
other end portion.
9
CA 02931538 2016-05-30
H8324110CA
The cable may be attached to the full ring and half rings using cable clamps
or the like. It will be
appreciated by one of ordinary skill in the art that other items may be used
in place of cable, for
example, steel chain. The pulleys can be adapted to receive such chain. In
addition other ways
of mounting the cable to the transfer block and to the conduit can be used,
besides the half ring
and full ring which in this example are made of steel.
[0031] When actuated in its down stroke the cylinder 48 moves the cable 50
so as to move the
block upward to a position C shown in dotted lines in Fig. 2 out of alignment
with the pump
opening to carry out circulation of molten metal in the furnace. This is
because the pump wall
opening 28 is unobstructed at its outlet, permitting free passage of the
pumped molten metal
between the pump and the charging well. When actuated in its up stroke the
cylinder 48 moves
the cable 50 to permit the transfer block 38 to move downward into a position
T in alignment
with the pump wall opening 28 to carry out transfer of the molten metal to the
exterior vessel 36.
This is because the transfer block 38 obstructs the pump wall opening 28 so
that the molten
metal is forced to travel from the pump, through the pump wall opening 28,
along the transfer
passageway 34 and out the conduit 39 into the exterior vessel 36.
[0032] The metal transfer conduit 39 is fastened to the transfer block 38
and extends from the
transfer passageway to a location outside the furnace above the vessel 36. A
plate or flanged
section of conduit 58 may be cast into the transfer block including threaded
openings. If a plate
is used, a flange of the conduit 39 may be bolted to the plate. When a flanged
conduit section 58
is cast into the transfer block, another flanged section of conduit 59 may be
fastened to it. The
flanged conduit section 58 and other longer flanged conduit section 59 and any
flanged elbow 61
may all be considered to form the transfer conduit 39 that is fastened to the
transfer block 38.
When the transfer block 38 is lowered to its transfer position T the conduit
39 moves from a
location above the vessel downward (dotted lines, Fig.3) to closer to an upper
mouth of the
vessel 36 (solid lines), reducing splashing of molten metal and resultant
detrimental generation
of oxides.
[0033] The transfer block 38 is formed of a castable refractory. One
composition of the
transfer block is a mixture of aluminum oxide and silicon carbide.
CA 02931538 2016-05-30
H8324110CA
[0034] It will be appreciated that various devices can be used to maintain
the transfer block in
position against the pump wall when the transfer operation is carried out. For
example, a frame
60 could be positioned and fixed to the pump wall 26 so that the transfer
block 38 is contained
by the frame and is only permitted substantial movement in a vertical
direction. In another
variation, the transfer block 38 could include an optional wedge 62a (or other
shaped protrusion)
that fits into a wedge recess 62b (or other shaped recess) in the furnace
floor 64 of the scrap
charging well. This would force the transfer block 38 against the pump wall.
One of ordinary
skill in the art in reading this disclosure may envision other ways of
maintaining the transfer
block against the pump wall, which would fall within the spirit and scope of
this disclosure.
100351 Moreover, the transfer passageway 34 may formed entirely by a
relatively light
refractory conduit rather than as an opening in a heavy refractory block. This
would also employ
a device for maintaining the mouth of the conduit in place against the pump
wall and over its
opening during transfer.
[0036] The device can be in the form of a kit as shown in Fig. 3 for
retrofitting an existing
furnace 10 with minimal effect on interruption of molten metal processing
operations. This kit
would permit a simple and cost effective way for the furnace to have selective
molten metal
circulation and transfer. The kit includes the transfer passageway 34 adapted
to be disposed
downstream of the pump wall 26 and to extend from alignment with the pump wall
opening 28
toward the exterior vessel 36 outside the furnace. Included are means for
moving the transfer
passageway into alignment with the opening and against the pump wall so as to
enable pumped
molten metal to be transferred from the furnace along the passageway to the
exterior vessel, and
for moving the transfer passageway out of alignment with the opening so as to
enable pumped
molten metal to circulate in the furnace. This means for moving the transfer
passageway
includes the support structure 44 with pulleys 46 and cable 50, and the
cylinder 48, and any input
display, PLC and the like.
[0037] In one example, the kit includes the transfer block 38 of refractory
material adapted to
be disposed downstream of the pump wall 26. The transfer block 38 is cast to
include the
11
CA 02931538 2016-05-30
H8324110CA
transfer passageway 34 inside of it that extends from alignment with the pump
wall opening 28
toward the exterior vessel 36. The transfer block 38 includes a face that
optionally slides on the
pump wall. Further included is the support structure 44 adapted to be fixed
over the furnace.
The pulleys 46 are carried by the support structure. The kit can include the
pneumatic or
hydraulic cylinder 48 positioned outside the furnace. Included is the cable 50
that is fastened to
and extends between the cylinder and the transfer block for movement along the
pulleys. When
actuated in its down stroke, the cylinder 48 moves the cable along the pulleys
so as to move the
transfer block 38 upward out of alignment with the pump wall opening 26 to
cause molten metal
circulation. When actuated in its up stroke the cylinder 48 moves the cable
along the pulleys so
as to cause the transfer block 38 to move downward into alignment with the
pump wall opening
26 to carry out transfer of molten metal to the vessel 36.
100381 The kit can include the transfer conduit fastened to the transfer
block and extending
from the transfer passageway to a location above the vessel.
100391 A furnace would be modified so as to employ the kit of the
disclosure by building the
support structure 44 above the furnace, e.g., fixing the vertical beams to a
top of the pump wall
of the furnace and including the horizontal beam. The support structure would
include the
rotatably fastened pulleys. This would be formed of heat resistant materials
such as steel. The
transfer block 38 would be cast so as to include the transfer passageway 34.
This would be
dimensioned so as to fit the particular furnace design. For example, the
passageway would be
cast into the block at a size and location where it would be capable of
covering the dimensions of
the archway in the pump wall when the block rests on the floor of the furnace
and to extend to a
sufficient angle and length at an elevation leading toward the vessel outside
the furnace. The
conduit 39 could also be tailored so as to extend at a suitable angle and
length outside the furnace
to accommodate the location and size of the exterior vessel (e.g., ladle or
crucible) to which the
molten metal is transferred. The conduit could extend to a location above the
vessel, for example.
The cylinder would be positioned outside of the furnace to keep it away from
the intense heat in
the furnace. The cable would be fastened to the cylinder and transfer block
and travel over the
pulleys.
12
CA 02931538 2016-05-30
H8324110CA
100401 In operation, the pump could operate continuously or intermittently,
whenever
circulation and/or transfer are desired. Circulation would permit molten metal
to travel from the
main hearth, into the pump well and into the pump, into any scrap charge well
and back to the
main hearth. In effect, circulation can be the default operation. During
circulation the cylinder
is in its down stroke so as to lift the block outside of alignment with the
pump wall archway.
Thus, molten metal freely travels from the pump well through the pump wall
archway into the
scrap charging well. Circulation can occur predominantly, until the transfer
block is moved to
cover the pump wall opening at which time transfer occurs.
[0041] When transfer is desired, the cylinder is actuated in its up stroke.
This moves the
transfer block 38 downward so as to align the transfer passageway 34 with the
archway in the
pump wall. The block optionally has its face 40 sliding against the face 42 of
the pump wall 26
and its weight resists displacement by the pumping molten metal stream into
the archway. When
the transfer block is moved into its transfer position the pump may be off.
Then once the transfer
block 38 is in its aligned transfer position and the exterior vessel is in
position, the pump can be
turned on, which moves the molten metal of the pump well into the transfer
passageway of the
transfer block 38, through any attached conduit 39 and into the exterior
vessel 36. The pump can
again be shut down when transfer is complete. Alternatively, the transfer
block 38 may be lifted
when transfer is complete, without shutting the pump off, ending the transfer
operation and
proceeding directly back to circulation mode.
[0042] Many modifications and variations will be apparent to those of
ordinary skill in the art
in light of the foregoing disclosure. Therefore, it is to be understood that,
within the scope of the
appended claims, the invention can be practiced otherwise than has been
specifically shown and
described.
13
